MIPS: Netlogic: XLP9XX USB support

XLP9XX has a USB 3.0 controller on-chip with 2 xHCI ports. The USB
block is similar to the one on XLP2XX, so update usb-init-xlp2.c
to handle XLP9XX as well.

Signed-off-by: Ganesan Ramalingam <ganesanr@broadcom.com>
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/6285/